| 摘要 |
PROBLEM TO BE SOLVED: To provide a cutting oil for wire saw, which is simple to handle, a wire saw cutting oil compsn., and a wafer cleaning method capable of realizing simple waste water treatment. SOLUTION: This cutting oil for wire saw comprises not less than 60 wt.% nonionic surfactant, which, when diluted by 20 times with water, has a cloud point of 0 to 100 deg.C and not more than 4 wt.% water. The wafer cleaning method comprises washing, with water, a wafer obtained by cutting an ingot by means of a wire saw using a wire saw cutting oil compsn. contg. a wire saw cutting oil and abrasive grains, heating the resultant waste water to a temp. above the cloud point of the nonionic surfactant contained in the waste water, separating the system into an oil phase and an aq. phase, and separating the oil phase contg. the nonionic surfactant from the waste water. |
